data link layer

Layer two, the second lowest layer in the OSI
seven layer model. The data link layer splits data into
frames (see fragmentation) for sending on the physical
layer and receives acknowledgement frames. It performs error
checking and re-transmits frames not received correctly. It
provides an error-free virtual channel to the network layer.
The data link layer is split into an upper sublayer, Logical
Link Control (LLC), and a lower sublayer, Media Access
Control (MAC).